Abstract: To optimize the best technique for extracting the total alkaloids from Sonchus brachyotus DC.. The single factor experiment was utilized to analyze the impact of the liquid-solid ratio, ultrasonic time, ultrasonic temperature, ultrasonic power, pH, ethanol concentration on the yield of total alkaloids. The method of response surface analysis with four factors and three levels was adopted to optimize the extraction process of total alkaloids, and the importance and the interactions of disparate factors were analyzed. The optimum technological circumstances were resolved as follows:solid-liquid ratio 1:30 g/mL, ultrasonic time 30 min, ultrasonic temperature 55℃, ultrasonic power 700 W, pH 5, ethanol concentration 75%, and the total alkaloids yield was 20.30%. Conclusion:the experimental consequences demonstrated that the mathematical model of quadratic polynomial had favorable predictability, and the total alkaloids extraction process was steady, feasible and repeatable.